U.S. patent application number 10/272699 was filed with the patent office on 2003-05-22 for method for manufacturing organic electroluminescence device.
Invention is credited to Ju, Sung Hoo, Kim, Sun Woong, Kim, Woo Young, Lee, Joo Hyeon, Lee, Won Geon.
Application Number | 20030096197 10/272699 |
Document ID | / |
Family ID | 26635551 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030096197 |
Kind Code |
A1 |
Lee, Joo Hyeon ; et
al. |
May 22, 2003 |
Method for manufacturing organic electroluminescence device
Abstract
Disclosed is a method for manufacturing an organic
electroluminescence device, which decreases the surface resistance
at side edges of pixels and increases the uniformity of the pixels,
thereby reducing degradation of the device, increasing the life of
the device, and improving the displaying sharpness of the device.
According to the method, at first, a transparent metal film is
deposited on a transparent substrate. Then, the transparent metal
film is wet-etched to form anodes respectively having a transverse
section whose side profiles are tapered at an angle between 70 and
90 degrees. Thereafter, an organic layer is formed on the anodes
and on the substrate, and then cathodes are formed on the organic
layer.
Inventors: |
Lee, Joo Hyeon;
(Kyoungki-do, KR) ; Kim, Sun Woong; (Seoul,
KR) ; Ju, Sung Hoo; (Kyoungki-do, KR) ; Kim,
Woo Young; (Seoul, KR) ; Lee, Won Geon;
(Seoul, KR) |
Correspondence
Address: |
Richard J. Streit
Ladas & Parry
Suite 1200
224 South Michigan Avenue
Chicago
IL
60604
US
|
Family ID: |
26635551 |
Appl. No.: |
10/272699 |
Filed: |
October 17, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10272699 |
Oct 17, 2002 |
|
|
|
09599238 |
Jun 22, 2000 |
|
|
|
Current U.S.
Class: |
430/318 ;
430/319; 430/321 |
Current CPC
Class: |
H01L 51/5209 20130101;
H01L 51/0021 20130101; H01L 27/3283 20130101; H01L 51/56 20130101;
H01L 51/5284 20130101 |
Class at
Publication: |
430/318 ;
430/319; 430/321 |
International
Class: |
H01J 001/62 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 1999 |
KR |
99-24195 |
Claims
What is claimed is:
1. A method for manufacturing an organic field electroluminescence
device, the method comprising the steps of: depositing a
transparent metal film on a transparent substrate; wet-etching the
transparent metal film to form anodes respectively having a
transverse section whose side profiles are tapered at an angle
between 70 and 90 degrees; forming an organic layer on the anodes
and on the substrate; and forming cathodes on the organic
layer.
2. A method as claimed in claim 1, wherein the anodes are
respectively formed to have a transverse section whose side
profiles are vertical, in the wet-etching step.
3. A method as claimed in claim 1, wherein the transparent metal
film is an indium tin oxide film,
4. A method as claimed in claim 3, wherein the indium tin oxide
film has a thickness of 2000 .ANG., the surface resistance is
8.OMEGA./.quadrature..
5. A method as claimed in claim 1, wherein said cathodes formed on
said organic layer are opposed to said anodes so that said cathodes
together with said anodes make a shape of a matrix.
6. A method as claimed in claim 1, wherein the surface resistance
of the anodes is in the range of 3 to 20.OMEGA./.quadrature..
7. A method for manufacturing an organic electroluminescence
device, the method comprising the steps of: preparing a transparent
substrate on which anodes are formed by patterning a transparent
metal film, the anodes respectively having a transverse section
whose side profiles are tapered at predetermined angles; forming a
dielectric film on the anodes and on the transparent substrate, in
such a manner that center portions of the anodes are exposed
through the dielectric film; forming black matrices on the
dielectric film, in such a manner that center portions of the
anodes are exposed through the black matrices; forming organic
layers on the center portions of the anodes; and forming cathodes
on the black matrices and the organic layers.
8. A method as claimed in claim 7, wherein the dielectric film is
an oxide film selected from the group consisting of a BaO film, a
Y.sub.2O.sub.3 film, an SiO.sub.2 film, an SiON film, and an SiNx
film.
9. A method as claimed in claim 7, wherein the black matrices are
opaque metal films selected from the group consisting of chrome
(Cr) films and copper (Cu) films.
10. A method as claimed in claim 7, wherein the dielectric film is
formed by a first shadow mask, by which the center portions of the
anodes are masked, and through which edges of the anodes and the
substrate are exposed.
11. A method as claimed in claim 7, wherein the black matrices are
formed by the first shadow mask, by which the center portions of
the anodes are masked, and through which the dielectric film is
exposed.
12. A method as claimed in claim 7, wherein the dielectric film and
the black matrices are formed by a photolithography and an
etching.
13. A method as claimed in claim 7, wherein the organic layers are
formed by a second shadow mask, through which the center portions
of the anodes are exposed, and by which the black matrices are
masked.
14. A method as claimed in claim 7, wherein the anodes are formed
by patterning an indium tin oxide film.
15. A method for manufacturing an organic electroluminescence
device, the method comprising the steps of: depositing a
transparent metal film on a transparent substrate; wet-etching the
transparent metal film to form anodes respectively having a
transverse section whose side profiles are tapered at an angle
between 70 and 90 degrees; forming an organic layer on the anodes
and on the substrate; and forming cathodes on the organic layer,
wherein the surface resistance of the anodes is in the range of 3
to 20.OMEGA./.quadrature..
Description
RELATED U.S. APPLICATION DATA
[0001] This application is a Continuation-in-Part of application
Ser. No. 09/599,238 filed Jun. 22, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method for manufacturing
an organic electroluminescence device, which decreases the surface
resistance at side edges of pixels and increases the uniformity of
the pixels, thereby reducing degradation of the device, increasing
the life of the device, and improving the displaying sharpness of
the device.
[0004] 2. Description of the Related Art
[0005] An organic electroluminescence device is a next generation
image display device, which is employed in a cellular-phone, a car
navigation system (CNS), a display panel of a game machine, a
notebook computer, a wall-mounted type television, etc.
[0006] Referring to FIG. 1 showing a conventional organic
electroluminescence device, anodes 11 extending in parallel in a
predetermined direction are formed on a transparent substrate 10
such as a glass. Each of the anodes 11 has a section whose side
profiles are tapered at predetermined angles. An organic layer 12
is formed on the anodes 11 and on the entire substrate 10. In this
case, the anodes 11 perform a function of supplying holes, and are
formed by means of an indium tin oxide (hereinafter, ITO) film
having a superior light-transmittivity and a superior
electric-conductivity, so that the light emitted from the organic
layer 12 can transmit through the anodes 11. Further, though not
shown, the organic layer 22 includes a hole-carrying layer, a
light-emitting layer, and an electron-carrying layer. A plurality
of cathodes 13 opposed to the anodes 11 are formed on the organic
layer 12. The cathodes 13 extend crossing over the anodes 11, so
that the cathodes 13 together with the anodes 11 form a shape of a
matrix. In this case, the cathodes 13 perform a function of
supplying the electrons, and are made from metal having a low work
function and a high stability in order to ensure a smooth supply of
the electrons.
[0007] That is, in the organic electroluminescence device as
described above, light is emitted and transmitted from the organic
layer 12 between the anodes 11 and the cathodes 13 by the voltage
applied between the anodes 11 and the cathodes 13.
[0008] In the meantime, due to the tapered side profiles of the
anodes 11, each of the anodes 11 has a relatively uniform surface
resistance at the middle portion thereof, while having a surface
resistance increasing as it goes toward both side edges of each of
the anodes 11. Accordingly, when the driving voltage is applied,
center portions of pixels or picture elements, at which the anodes
11 and the cathodes cross over each other, begin to emit light at a
relatively low voltage, while edges of the pixels emit light at a
relatively high voltage. Therefore, not only the displaying
sharpness is deteriorated, but also it is impossible to operate the
device for a relatively long time because the side edges of the
pixels are degraded when the driving voltage is elevated.
SUMMARY OF THE INVENTION
[0009] Accordingly, the present invention has been made in an
effort to solve the problems occurring in the related art, and it
is an object of the present invention to provide a method for
manufacturing an organic electroluminescence device, which
decreases the surface resistance at side edges of pixels and
increases the uniformity of the pixels, thereby reducing
degradation of the device, increasing the life of the device, and
improving the displaying sharpness of the device.
[0010] In accordance with one aspect of the present invention,
there is provided a method for manufacturing an organic
electroluminescence device, the method comprising the steps of:
[0011] depositing a transparent metal film on a transparent
substrate;
[0012] wet-etching the transparent metal film to form anodes
respectively having a transverse section whose side profiles are
tapered at an angle between 70 and 90 degrees;
[0013] forming an organic layer on the anodes and on the substrate;
and
[0014] forming cathodes on the organic layer.
[0015] Preferably, the anodes are respectively formed to have a
transverse section whose side profiles are vertical, in the
wet-etching step. More preferably, the transparent metal film is an
indium tin oxide film.
[0016] In accordance with another aspect of the present invention,
there is provided a method for manufacturing an organic
electroluminescence device, the method comprising the steps of:
[0017] preparing a transparent substrate on which anodes are formed
by patterning a transparent metal film, the anodes respectively
having a transverse section whose side profiles are tapered at
predetermined angles;
[0018] forming a dielectric film on the anodes and on the
transparent substrate, in such a manner that center portions of the
anodes are exposed through the dielectric film;
[0019] forming black matrices on the dielectric film, in such a
manner that center portions of the anodes are exposed through the
black matrices;
[0020] forming organic layers on the center portions of the anodes;
and
[0021] forming cathodes on the black matrices and the organic
layers.
[0022] Preferably, the dielectric film is an oxide film selected
from the group consisting of a BaO film, a Y.sub.2O.sub.3 film, an
SiO.sub.2 film, an SiON film, and an SiNx film.
[0023] Also, it is preferred that the black matrices are opaque
metal films selected from the group consisting of chrome (Cr) films
and copper (Cu) films.
[0024] More preferably, the dielectric film is formed by a first
shadow mask, by which the center portions of the anodes are masked,
and through which edges of the anodes and the substrate are
exposed. The black matrices may be formed also by the first shadow
mask, by which the center portions of the anodes are masked, and
through which the dielectric film is exposed.
[0025] In this case, the dielectric film and the black matrices are
formed by a photolithography and an etching. Also, the organic
layers are formed by a second shadow mask, through which the center
portions of the anodes are exposed, and by which the black matrices
are masked. The anodes may be formed by patterning an indium tin
oxide film.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The above objects, and other features and advantages of the
present invention will become more apparent after a reading of the
following detailed description when taken in conjunction with the
drawings, in which:
[0027] FIG. 1 is a sectional view of a conventional organic
electroluminescence device;
[0028] FIGS. 2A to 2C are sectional views for describing a method
for manufacturing an organic electroluminescence device according
to an embodiment of the present invention; and
[0029] FIGS. 3A to 3E are sectional views for describing a method
for manufacturing an organic electroluminescence device ccording to
another embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] The above and other objects, characteristics, and advantages
of the present invention will become apparent from the following
description along with the accompanying drawings.
[0031] Hereinafter, described in detail will be several preferred
embodiments of the present invention, with reference to the
accompanying drawings. In the following description and drawings,
the like parts having the same function will be designated by the
same numerals, and repetition of the same description will be
avoided.
[0032] FIGS. 2A to 2C are sectional views for describing a method
for manufacturing an organic electroluminescence device according
to an embodiment of the present invention.
[0033] Referring to FIG. 2A, a transparent metal film such as an
ITO film is deposited on a transparent substrate 20 such as a
glass, and a photo-resist pattern (not shown) is formed thereon by
a photolithography. Thereafter, the ITO film is etched by a wet
etching by utilizing the photo-resist pattern as a shadow mask, so
as to form a plurality of anodes 21 extending in parallel in a
predetermined direction and being spaced at predetermined
intervals. The anodes 21 respectively has a section whose side
profiles are nearly vertical, for example, tapered at about 70 to
90 degrees. In this case, the wet etching should be carefully
performed, so as not to be excessively etched.
[0034] The surface resistance of the anodes is in the range of 3 to
20.OMEGA./.quadrature., wherein the surface resistance depends on
the thickness of ITO film. For example, when the ITO film has a
thickness of 2000 .ANG., the surface resistance is
8.OMEGA./.quadrature.. In this case, light emitted from each pixel
becomes uniform and the generation of shorts can be prevented.
[0035] Referring to FIG. 2B, an organic layer 22 is formed on the
anodes 21 and on the entire substrate 20. The organic layer 22
includes a hole-carrying layer, a light-emitting layer, and an
electron-carrying layer, though not shown in the drawing.
[0036] Referring to FIG. 2C, a metal film is deposited on the
organic layer 22, and then is patterned so as to form a plurality
of cathodes 23 on the organic layer 22, which are opposed to the
anodes 21. The cathodes 23 extend crossing over the anodes 21, so
that the cathodes 23 together with the anodes 21 make a shape of a
matrix. In this case, the metal film has a low work function and a
high stability.
[0037] In other words, since the anodes 21 respectively have
vertical side profiles, the pixels respectively have a uniform
surface resistance at both the center portion and the side edges of
each pixel. Therefore, the center portion and the side edges of
each pixel emit light at the same driving voltage, thereby
improving the sharpness of display and preventing the degradation
of the side edges of each pixel.
[0038] FIGS. 3A to 3E are sectional views for describing a method
for manufacturing an organic electroluminescence device according
to another embodiment of the present invention.
[0039] Referring to FIG. 3A, a transparent metal film such as an
ITO film is deposited on a transparent substrate 30 such as a
glass, and a plurality of anodes 31 are formed by patterning the
metal film through a photolithography and an etching. The anodes 31
extend in parallel in a predetermined direction and are spaced at
predetermined intervals. The anodes 31 respectively have a section
whose side profiles are tapered at predetermined angles as those in
the prior art shown in FIG. 1.
[0040] The surface resistance of the anodes is in the range of 3 to
20.OMEGA./.quadrature., wherein the surface resistance depends on
the thickness of ITO film. For example, when the ITO film has a
thickness of 2000 .ANG., the surface resistance is
8.OMEGA./.quadrature.. In this case, light emitted from each pixel
becomes uniform and the generation of shorts can be prevented.
[0041] As shown in FIG. 3B, disposed above the anodes 31 is a first
shadow mask 100, by which center portions of the anodes 31 are
masked, and through which side edges of the anodes 31 and the
substrate 30 are exposed. Then, a dielectric film 32 having holes
is formed thereon by means of the first shadow mask 100, so that
the center portions of the anodes 31 are exposed through the holes
of the dielectric film 32. Preferably, the dielectric film 32 is
formed as an oxide film such as a BaO film, a Y.sub.2O.sub.3 film,
an SiO.sub.2 film, an SiON film, and an SiNx film. Thereafter, as
shown in FIG. 3C, black matrices 33 are formed on the dielectric
film 32 by means of the first shadow mask 100. Preferably, the
black matrices 33 are formed as opaque metal films such as Cr films
and Cu films. Also, the dielectric film 32 and the black matrices
33 may be formed by a photolithography and an etching.
[0042] As shown in FIG. 3D, disposed above the black matrices 33 is
a second shadow mask 200, by which center portions of the anodes 31
are exposed, and through which the black matrices 33 are masked.
Then, organic layers 34 are formed on the center portions of the
anodes 31 by means of the second shadow mask 200. In this case,
though not shown, each of the organic layers 34 includes a
hole-carrying layer, a light-emitting layer, and an
electron-carrying layer. By the above construction, light is
emitted from center portions of the pixels by the organic layers 34
formed only at the center portions of the anodes 31, while the
black matrices 33 block off the light above the side edges of the
anodes 31, so that the sharpness of display is improved and a
degradation of edges of the pixels is prevented.
[0043] Thereafter, as shown in FIG. 3E, a plurality of cathodes 35
opposed to the anodes 31 are formed on the organic layers 34 and
the black matrices 33. The cathodes 35 extend crossing over the
anodes 31, so that the cathodes 35 together with the anodes 31 make
a shape of a matrix. In this case, the cathodes 35 are formed by
means of a third shadow mask for cathodes or by a photolithography
and an etching.
[0044] In the method for manufacturing an organic
electroluminescence device according to the present invention as
described above, the anodes are formed to have vertical side
profiles, so that the surface resistance is constant both at the
center portions and at the side edges of the pixels. In this case,
a simultaneous light-emitting from the entire portions of the
pixels at the same driving voltage is enabled. According to another
aspect of the present invention, the light toward the side edges of
the anodes is blocked off, so that only the center portions of the
pixels emit light. Therefore, the present invention not only
improves the sharpness of display, but also prevents degradation of
the side edges of the pixels of the organic electroluminescence
device.
[0045] As described above, in the present invention, the taper
angle of anodes is in the range of 70 to 90.degree., thereby
improving the uniformity light emission. And, the surface
resistance of anodes is in the range of 3 to
20.OMEGA./.quadrature., thereby the light emitted from each pixel
becomes uniform and the generation of shorts can be prevented.
[0046] While there have been illustrated and described what are
considered to be preferred specific embodiments of the present
invention, it will be understood by those skilled in the art that
the present invention is not limited to the specific embodiments
thereof, and various changes and modifications and equivalents may
be substituted for elements thereof without departing from the true
scope of the present invention.
* * * * *